title: The role of carbon dioxide as an orientation cue for western corn rootworm larvae within the maize root system: implications for an attract-and-kill approach.
abstract: BACKGROUND
  Western corn rootworm larvae use CO2 to locate maize roots. However, the importance of CO2 as a specific orientation cue close to maize roots has not been investigated unequivocally. This study aimed at elucidating the effect of CO2 -emitting capsules in combination with a soil insecticide (Tefluthrin = attract and kill) within the root system. We hypothesized that the capsules would result in aggregation of the larvae at the soil insecticide, thus increasing its efficacy. A nondestructive observation device was used to study larval distribution and behaviour.
  
  
  RESULTS
  Spatial analysis of distance indices (SADIE) revealed aggregation of the larvae around the capsules in an attract-and-kill treatment after 4 h, which was not found with the conventional treatment without the capsules. However, larval mortality did not differ between treatments.
  
  
  CONCLUSIONS
  CO2 is a weak attractant for western corn rootworm larvae within the root system. Consequently, an attract-and-kill strategy based on a CO2 product will not contribute to better control compared with conventional Tefluthrin applications. Host-specific compounds, combined with a CO2 source, should be used to target more larvae, making attract and kill a feasible management option against this pest.
authors.affiliation: Georg-August University, Department of Crop Science, Agricultural Entomology, Göttingen, Germany.
authors.forename: Mario
authors.initials: M
authors.lastname: Schumann
authors.forename: Anant
authors.initials: A
authors.lastname: Patel
authors.forename: Marina
authors.initials: M
authors.lastname: Vemmer
authors.forename: Stefan
authors.initials: S
authors.lastname: Vidal
mesh_terms: D000818:Animals; D001522:Behavior, Animal; D002245:Carbon Dioxide / Q000378:metabolism*; D001517:Coleoptera / Q000502:physiology*; D003521:Cyclopropanes / Q000633:toxicity; D006845:Hydrocarbons, Fluorinated / Q000633:toxicity; D007300:Insect Control / Q000379:methods*; D007306:Insecticides / Q000633:toxicity; D007814:Larva / Q000502:physiology*; D018517:Plant Roots; D012987:Soil; D003313:Zea mays
chemical_list: D003521:Cyclopropanes; D006845:Hydrocarbons, Fluorinated; D007306:Insecticides; D012987:Soil; D002245:Carbon Dioxide; C489827:2,3,5,6-tetrafluoro-4-methylbenzyl (Z)-(1RS)-cis-3-(2-chloro-3,3,3-trifluoroprop-1-enyl)-2,2-dimethylcyclopropanecarboxylate
keywords: Diabrotica virgifera virgifera; Tefluthrin; orientation cue; root herbivore